Apparatus for cleaning tubes of heat exchanger



June 16, 1959 A. H. HELLER 2,890,362 KPPARATUS FOR cmzmmc TUBES OF HEAT EXCHANGER Filed Sept. 15, 1955 r. V 4\ 5 lll uul na m lo I h I16 INVENTOR.

ANTON H. HELLER ited States Patent APPARATUS FOR CLEANING TUBES OF HEAT EXCHANGER Anton H. Heller, Levittown, N.Y., assignor, by direct and mesne assignments, to RO-AN Heat Reclaimer Corp., Bay Shore, N.Y., a corporation of New York Application September 15, 1955, Serial No. 534,474

3 Claims. (Cl. 257-1) This invention relates to heat exchangers, heat reclaimers, or the like, and in particular to novel method and apparatus for removing soot, rust, scales and other heat inhibiting substances from about the coils, or tubes, or other similar, heat exchanger elements.

To those who are skilled in the art, it will be appreciat ed that the greatest loss of heat from heating systems is up through the chimney or stack. In an attempt to reduce heat losses and increase the efliciency of heating systems, heat exchangers or reclaimers are generally installed between the heater and the chimney.

The heat exchanger or reclaimer, operating on the principle of heat conduction, removes the heat from the hot gases that normally escape up the chimney by causing such hot gases to pass over a bank of cooler airfilled or water-filled coil or tube elements. The medium in the coils or tubes is thus heated, and a blower installed at the rear of the tubes blows the then heated medium to a location to be warmed. Thus, the heat exchanger or reclaimer utilizes the heat of the waste gases that normally escape up the chimney to result in a more efiicient heating system.

It is well known that by utilizing what would normally be-considered hot waste chimney gases, and causing the same to pass over heat exchanger elements, large amounts of foreign matter in the gases are deposited thereon. Such deposits, whether they be soot, rust, scales or other substances, act as an insulator and consequently lower the efficiency of heattransmission from the hot chimney gases to the relatively cooler medium in the exchanger coils or tubes. Continued eificiency of heat transfer from the heating medium to the medium to be heated is,

therefore, dependent upon the cleanliness of the heat the insulating deposits.

The purpose of the instant invention is to keep clean the coils or tubes of the heat exchanger or the like to insure continued efliciency of transfer of heat from the hot waste chimney gases to, the cool medium in the coils or tubes. Accordingly, an object of the instant invention resides in providing a novel apparatus and method to clean and keep clean the coils or tubes during the operation of the heat exchanger.

The problem of cleaning the heat exchanger coil or tube elements is made difficult because of the large change of size in their circumference or periphery as they are alternately heated and cooled. Attemps in prior art devices as the Hoppes Patent No. 1,898,727, and Thompson Patent No. 2,357,239, have failed to overcome the problem. Hence, another object of the invention is to provide a cleaningapparatus that cleans the full or substantially the full periphery or circumference of each coil or tube element of the heat exchanger in one cleaning sweep, and moreover, is capable of cleaning each coil or tube of the bank of coils or tubes simultaneously.

A further object of the invention resides in the provision of a cleaning apparatus having novel cleaning means ice that constantly engage about the full or about substantially the full circumference or periphery of the heat exchanger coils or tubes, expanding and contracting therewith during the heating and cooling of the same.

Another object of the invention is to provide a cleaning apparatus for heat exchangers which is simple in structure and design, economical and fool-proof in operation, and easily maintained and repaired.

Still another object of the inventions is to provide a novel method of cleaning the full or substantially the full circumference or periphery of each heat exchanger coil or tube in a bank by a single sweeping movement of the cleaning apparatus.

Other and further objects of my invention reside in the structures and arrangements hereinafter more fully described with reference to the accompanying drawings in which:

Fig. l is a perspective view of a heat exchanger, or reclaimer, or the like with a portion thereof cut away to more clearly show the inventive details of the same.

Fig. 2 is a plan view of an operating screw or moving mechanism.

Fig. 3 as taken substantially along lines 4-4. away to disclose a cleaner element thereof. b

Fig. 4 is a sectional side view of the structure shown in Fig. 3 is taken substantially along lines 4-4.

Fig. 5 is a partial front view of the tube sweeper with the front plate thereof cut away to show a modified cleaner element. 4

Fig. 6 is a sectional side view of Fig. 5 taken substantially along lines 6---6. t

Fig. 7 is a partial front view of a modified tube sweeper and cleaning element, and

Fig. 8 is a sectional side view of Fig. 7 taken substantially along lines 88.

Referring now to the drawings and in particular to Fig. 1 wherein the heat exchanger or heat reclaimer, or the like, is generally identified by the numeral 10. Since the instant invention may be applicable to many other structures embodying the principles of the aforementioned items, for ease of description the term heat exchanger will be employed hereinafter in a general manner to cover such items.

The heat exchanger 10 comprises a main or body cover 12 closed at its forward end by a front cover plate 14 secured thereto by fasteners 16. The rear end of the heat exchanger 10 is closed by arear cover 18 secured by fasteners 16 to the body 12 in substantially the same manner as is'the front cover 14. i

Mounted within the heat exchanger is a bank of exchanger elements wherein each element of the bank is identified by the numberal 20. The elements 20 are mounted in rows, with each row generally being staggered relative to the next adjacent one while the elements in each row are spaced laterally relative to each other.

The elements 20 extend lengthwise within the interior of the heat exchanger 10 and are securely and suitably mounted at their forward ends to the front cover plate 14. The rear or back ends of the elements 20 are similarly securely and suitably mounted on a standard 22, see Fig. 1.

The four edges of the standard 22 abut and fit against the corresponding four interior walls of the main cover 12 to provide a rear support for the bank of elements 20. From Fig. 1 it will be noted that the standard 22 is spaced slightly from the rear cover plate 18 to provide an air blower chamber, not identified.

To those who are familiar with heat exchangers and the like, it will be understood that the cooler medium which it is desired to heat is blown through the bank of hollow elements 20. To do this, there is a blower 24 securely mounted by bracket 25 on the rear cover plate element 20 of thebank of elements.

1 8. In theinstant device the blower .24 sucks the cooler air from about the exterior of the heat exchanger and blows it into the blower chamber formed between the cover plate .18 and the standard 22. The cooler air blow into the blower chamber is forced into the hollow the rear ends of each of the elements 20 of the bank and out through their forward ends, there to be conducted to an area to be warmed.

This cooler air in the bank of elements 20 is heated by the relatively hotter waste gases which pass through the body of the heat exchanger 10. The hot waste gases .are directedinto the body of the heat exchanger 10 from a heating unit (not shown) by a flue pipe (not shown) connected .at the lower part of the exchanger at a flue connector 26. The ,hot waste gases circulating about the heat exchanger'ele'ments 20, heat the same, and in turn,

,heat the relatively coolerair being blown therethrough.

The hot waste chimney gases continue upwardly and out of the heat exchanger 10 by way of a'connector 28 which is secured toa chimney flue (not shown).

As the hot waste chimney gases are baflled by the cooler elements 20, deposits of soot, dust, and other'insulating materials form about their outsides. As previously mentioned, such deposits interfere with the effective transfer of heat from the hot waste gases to the cooler fluid medium in the elements 20. Therefore, to maintain the efficiency of the heat exchanger 10 at an econornical rate, periodic removal of the deposits is necessary. To this 'end a cleaning apparatus preferably operated by an electric motor, is employed to clean each In the instant disclosure such apparatus is operated to clean the full or substantially the full periphery of each element, and if there is a bank'of elements as has been described, each element in the bank will be cleaned simultaneously.

"Essentially, the cleaning apparatus for cleaning the heat exchanger elements 20 comprises a sweeper apparatus generally identified by the numeral 30. In detail, the sweeper apparatus 30 comprises a center guide plate member 32 anda pair of inner and outer face plates 34. The sweeper apparatus 30is provided with a plurality of spaced openings 36 defined in the inner and outer plates 34. These openings 36. correspond in number and relative positionto the number and relative position of each element of the bank of elements 20, so that each meet the elements 20 extends through a corresponding opening 36 in ,the sweeper apparatus 30.

At substantially the center of the bank of heat exchanger elements 20 there is a double or reversibly threaded screw 38. The operating screw 38 is bearingly mounted at its rear end 42in anopening in the standard 22, while its forward end is bearingly mounted in a similar manner (not shown) in the front cover plate 14.

The sweeper member 30 is bearingly mounted on the screw 38, and is caused to move when the screw rotates, by virtueof aguide collar 40 (see Fig. 2). The collar 40 is secured to the sweeper member 30 and has suitable means (not shown), engageable within the grooves of the reversible threads of the screw to guide the longitudinal movement of the sweepermember therealong.

The reversibly threaded screw 38-is rotated preferably by the intermediaryof a'motor 44 carrying a worm 46 whichengages and'drives a worm wheel 48. The worm wheel 48 is secured to an extended end 49 of the screw 38. Hence, driving operation of the motor 44 will cause the screw 38 to rotate and as a result thereof move the sweepermember 30 longitudinally or lengthwise of the bank ofelements 20. The sweeping or cleaning apparatus 3.0,rnoves first in one direction of the length of the elements 20 and then when'it reaches the end of the screw 38, it automatically shifts-in movement in the opposite direction along the length of the bank of elements.

To those who are familiar with heat-exchangers, it will :be understood that the heat exchanger tube or coil ele nient 20 xp ien e great chan in P r phera size when heated by the hot waste gases and then cooled when not in use. Thus, the mere sweeping movement of the sweeper member 30 across the length of the elements 20, without more, will not serve to clean away the deleterious deposits. This is not possible since, as mentioned preiously, the openings 36 are of such a diameter as to be greater than the diameter of the elements 20 even after the same have been heated and expanded to their fullest extent.

This expansion and contraction has therefore presented a cleaning problem which has not been solved heretofore. In order to overcome the difiiculty and to eliminate the problem, the center guide plate 32 of the sweeper member 30 is formed with openings 50 which are larger in size than the previously mentioned openings 36. Each opening 5c coincides in relative location with a set of the openings 36 in the inner and outer face plates 34. Mounted within each of the larger openings 50 is a cleaning device or element to be described.

In the embodiment shown in Figs. 3 and 4, the cleaning element52 is a fibrous substance. Cleaning element 52 is a metallic wool, porous and coarse in nature, and the fibers of which, because of the porosity, may move or yield relatively to each other. The-resultis a pliable, flexible, resilient element capable of "yielding under pressure and returning-to its original shape and size after pressure thereon is removed.

There are a plurality of the cleaning elements 52, each one of which is seated in -a respective one of the larger openings 50 of the center plate 32 and secured therein from sidewise movement by the inner and outer face plates 34. Each cleaning element '52 is provided with an opening (not numbered),-the dimension of which is slightly smaller than the normal outside peripheral dimension of the heat exchangerelement 20 when the same is in its cooled contracted condition.

As a result, when the cleaning elements 52 are positioned within their respective mounting openings 50 in the sweeper apparatus 30, each cleaning element 52 completely encloses about the outer periphery of its corresponding heat exchanger element to engage the same;

The degree of tension with which the cleaning elements 52 heat on and about their respective exchanger elements 20 is sufficient to provide a scraping or cleaning'engagement as the sweeper apparatus 30 is movedlengthwise along or longitudinally relatively to the bank of elements.

As it will be recognized, the width of the sweeper apparatus 30, and accordingly, the width of the cleaning elements 52 may be varied. It is noted however, that the elements 52 each constantly encircle and enclose a lengthwise portion of the periphery of its respective heat exchanger element. When the'hot waste chimney gases heat the elements 20, thereby causing them to expand and change. in size, the walls of the opening in the porous flexible cleaning elements 52 yield to permit such expansion.

Yet, on the other hand, when the heating equipment is shut OE and the heat exchanger elements 20 contract in peripheral size, the cleaning elements 52 flex and resiliently expand to account for such contraction of the heat exchanger element. In this manner, the heat exchanger elements are constantly encircled and peripherally engaged by the cleaning members 52.

In operation, the blower 25 and screw motor 44 are electrically connected with the heating equipment and are automatically operated therewith. The reversibly threaded screw 38 is rotated in place. Cleaning apparams 30 is then moved lengthwise-relatively to the bank of heat exchanger elements 20 by. the collar 40, first in one direction of their length, during which each of the elements of the bank are cleaned simultaneously by their respective cleaning elements 52, andthen because the sweeper 30 is automatically reversed in its direction of movement, in the opposite direction oftheir lengths.

although a plurality. of cleaningelements 52 are ena- 'of cleaning heat exchanger elements or the like.

ployed, one for each heat exchanger element 20, it is within the contemplation of the invention that a single such metallic wool or fibrous member may be provided. It is also within the contemplation of the invention that such cleaning element or elements 52 may clean heat exchanger elements 20 of varying cross-sectional shapes and sizes.

In the embodiment shown in Figs. and 6, the cleaning apparatus 130 being similar to that shown in Figs. 1 to 4, comprises a center plate 132, and inner and outer face plates 134. Openings 136 in the face plates 134, are larger than the greatest expanded size of the respective heat exchanger element 20 passing therethrough to enable such expans ion. Mounted within each of the openings 150 in the center plate 132, is a flexible, resilient cleaning element 152. The cleaning element 152 is ringshaped, andhas a normal unexpanded convolution of greater than 360, and at all times, a convolution of at least 360 l Like the cleaning element 52 described in Figs. 1 to 4, when the cleaning element 152 is seated about its respective heat exchanger element 20, it completely encircles the same and bears with suflicient tension against'its periphery to wipe or scrape off the inhibiting deposits as the cleaning apparatus 130 is moved. Again, as in the previous embodiment, the cleaning sweeper 130 may be operated to move lengthwise of the elements 20 or bank of elements, by the motor rotated reversibly threaded screw 38.

As the heat exchanger elements 20 expand, so do the flexible cleaning elements 152 thereabout. Expansion of the cleaning elements 152 is permitted by the enlarged size of the seating openings 150 in the center plate 132.

On the other hand, when the elements 20 cool and contract, the resilient, ring-shaped cleaning elements 152 automatically yield to constantly retain their cleaning engagement. The extent of the convolution of the cleaning element 152 is such as to assure complete peripheral encirclement of its respective heat exchanger element 20 at all times.

Referring to the embodiment of Figs. 7 and 8, the cleaning apparatus 230 may also be operated for lengthwise movement relatively to the bank of heat exchanger ele ments 20 by the motor driven screw 38 as in Figs. 1 to 4. The cleaning apparatus 230 includes a sweeper member 232 having enlarged openings 250. Mounted within each opening 250 is a cleaning element 252.

The cleaning element 252 is in the form of a split ring, split at 254 so that it may flex and yieldingly expand with the heated expansion of the heat exchanger element 20 which it is adapted to clean. Each cleaning element 252 has a normal convolution of 360. When in normal conditon, the cleaning element 252 completely encircles a lengthwise portion of its respective heat exchanger element 20. It bears with sufficient tension against the heat exchanger element 20, to scrape or clean the same as the cleaning apparatus 230' is moved longitudinally.

Each cleaning element 252 is provided with side guides 234 which insure constant guided mounting thereof on the plate 232 and longitudinal movement therewith. Therefore, as the heat exchanger elements 20 are heated and expand, the cleaning elements 252 thereabout yieldingly expand to a convolution of less than 360 and to less than full encirclement of the periphery of the heat exchanger elements. However, due to their resilient construction, each cleaning element 252 resiliently contracts about and constantly remains in cleaning engagement with its respective heat exchanger element. Thus, whether the heat exchanger element 20 expands or contracts, it will be engaged by the cleaning element 252. The degree of peripheral encirclement however, will be in accordance with the degree of expansion or contraction of the heat exchanger elements.

Principally, the invention provides a novel method In carrying out the objects of the novel method, novel apparatuses have also been invented whereby the expansion and contraction necessarily attendant in such devices have been taken into account and provided for. Thus, the dilficulties normally attendant in cleaning heat exchanger elements or the like, have been eliminated. Although specific apparatuses have been disclosed, it will be readily recognized that other flexible resilient cleaning element constructions may also be adaptable in carrying out the novel cleaning method.

From the foregoing it will be obvious that the novel cleaning apparatus disclosed is simple in construction and operation, and easily maintained. Moreover, as the cleaning apparatus progressively and periodically moves back and forth relatively to the bank of heat exchanger elements, it cleans the full outer periphery of each element and in turn simultaneously cleans each element in the bank.

In the embodiment of Figs. 7 and 8, the extent of encirclement, and therefore the portion of the periphery of each heat exchanger element cleaned, depends upon the expansion of the heat exchanger elements 20 themselves. j

Thus, while there have been shown and described and pointed out the fundamental novel features of the invention as applied to several preferred embodiments thereof, it will be understood that various omissions, substitutions and changes in the form and details of the devices and elements illustrated and in their operations may be made by those skilled in the art. This may be done without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

I claim:

1. In a heat exchanger or the like, having a bank of expansible and contractible heat exchanger elements, a cleaning apparatus movable lengthwise of said bank of elements, said apparatus comprising a center guide member, a pair of plates secured to opposite sides of said guide member to secure the same from movement relative thereto, a plurality of spaced sets of openings defined in said plates and member, said plurality of spaced sets of openings corresponding to the number and relative position of each one of said elements of said bank to receive therein its corresponding heat exchanger element, said openings in said plates being larger than the expanded size of the element received therein, said openings in said guide member being larger in size than the openings in said plates of its corresponding set, metallic wool cleaning means in said larger openings of said guide member restricted by the confines of its respective opening from radial movement relative to said guide member and from longitudinal movement relative to said guide member by said face plates, said cleaning means each having an openings of a size smaller than the normal size of said heat exchanger element to be cleaned thereby and the fibers thereof encircling and engaging the full periphery of said tube and yieldable to expand and contract in accordance with the expansion and contraction of its respective heat exchanger element to clean the same during the movement of said cleaning apparatus.

2. In a heat exchanger or the like, having at least a heat exchanger element that is expansible and contractible in size in response to changes in temperature, a cleaning apparatus movable along said heat exchanger element and including a guide member and inner and outer plates on opposite sides of said member fastened thereto against relative movement, said. guide member and plates each having openings defined therein larger than the peripheral expanded size of said heat exchanger element to receive the same, said opening defined in said guide member being larger than said openings in said plates, and metallic wool cleaning means mounted in said opening of said guide member and restricted by the confines thereof against radial movement relative to said guide member and from longitudinal movement relative to said guide member by said side plates, said cleaning means having ran=opening smaller than the normal peripheral size of said .heat exchanger element to receive the same therein and the fibers thereof being movable in accordance with the expansion and contrac tion of said heat exchanger element to engage and :clean the full periphery of vthe same during the movement of said cleaningapparatus.

3. In a heat exchanger or the like, having at least a heat exchanger element that is expans'ible and contractible peripherally according to'the degree of heat to which it is subjected, a cleaning apparatus movable lengthwise along said element to clean the same, said cleaning apparatus comprising a metallic wool cleaning means having an opening smaller in size than the periphery of said heat exchanger element 110 engagingly receive a lengthwise portion of the full periphery of the same,

a guide member having an ope'ningdefined therein larger than the peripheral size of said element to receive the same therein and to receive said ;cleaning means to restrict the same from radial movement relative to said heat exchanger element to be cleaned thereby, and plates on opposite sides of said guide member secured thereto against relative movement, said plates each having an opening defined therein larger than the expanded peripheralsize of said heat exchanger element and smaller than said guide member opening to restrict the cleaning means from lengthwise movement relative to said guide member but to enable the fibers of said cleaning means to move lengthwise thereinto during the lengthwise movement of said cleaning apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 352,730 an -s Nov. 16, 1886 674,9'1l} Hebden May, 28, 1901 1,898,727 Hoppes Feb. 21,- 1933 2,213,923 Stuart Sept. 3, 1940 2,487,626 Wittnflan Nov'. 8, 1949 2,772,784 Cyphers et al. Dec. 4, 1956 FOREIGN PATENTS 375,132 Great Britain June 23, 1932 1,053,255 France u, Feb. 1, 195,4 

